docs: def root_indices(sec_list):
      """
      Returns the index of all sections without a parent.
      """
      roots = []
      for i,section in enumerate(sec_list):
          sref = h.SectionRef(sec=section)
          # has_parent returns a float... cast to bool
          if sref.has_parent() < 0.9:
              roots.append(i)
      return roots